Oregon (ⁱ/ˈɔrɨɡən/ ORR-ə-gən) is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern boundaries, respectively. The area was inhabited by many indigenous tribes before the arrival of traders, explorers, and settlers who formed an autonomous government in Oregon Country in 1843. The Oregon Territory was created in 1848, and Oregon became the 33rd state on February 14, 1859.

Oregon is the 9th most extensive and the 27th most populous of the 50 United States. Salem is the state's capital and third-most-populous city; Portland is the most populous. Portland is the 29th-largest U.S. city, with a population of 583,776 (2010 US Census) and a metro population of 2,241,841 (2009 estimate), the 23rd-largest U.S. metro area. The valley of the Willamette River in western Oregon is the state's most densely populated area and is home to eight of the ten most populous cities.

A state fair is a competitive and recreational gathering of a U.S. state's population. It is a larger version of a county fair, often including only exhibits or competitors that have won in their categories at the more-local county fairs.

Originally a state fair was just a competitive exhibition of livestock in various competitions, the display of farm products which were not necessarily for sale, and the competition among various fair goers and participants in such categories as handicrafts, baked goods, jams and jellies, etc., but has since been expanded to include carnival amusement rides and games, music, races, tests of strength and skill, etc. Large fairs can see more than a million visitors over the course of a week or two. The first official U.S. state fair was in Detroit, Michigan in 1849.

Events similar to state fairs are also held annually in each state capital in Australia, known as Royal Shows. Australian Royal shows are organized by state agricultural and horticultural societies, and are described further in the agricultural show article.

The Oregon State Fair is the official state fair of the U.S. state of Oregon. It takes place every August–September at the 185-acre (0.75 km²) Oregon State Fairgrounds located in north Salem, the state capital, as it has almost every year since 1862. In 2006, responsibility for running the fair was delegated to the Oregon State Parks and Recreation Department, and the division is now known as the Oregon State Fair & Exposition Center (OSFEC), which holds events on the fairgrounds year-round.

As Oregon agriculture expanded in the early 19th century many communities formed agricultural associations for the purpose of sharing information on farming practices and resources. These groups began to organize county fairs such as the Yamhill County Fair (1850). Shortly thereafter the Oregon Farmer newspaper began calling for a statewide fair. A group of farmers known as the Oregon Fruitgrowers Association organized the first unofficial state fair in 1858. That year is recognized as the official anniversary year of the fair.